A poultry disease known as coccidiosis (also referred to as coccidia, or cocci) is caused by the parasite Eimeria. The various different species of Eimeria that specifically effect poultry include at least Eimeria tenella, Eimeria maxima, Eimeria acervulina, Eimeria mivati, Eimeria mitis, Eimeria brunetti, Eimeria necatrix, Eimeria meleagrimitis, Eimeria adenoeides, and Eimeria gallopovonisl. Coccidiosis causes a range of problems in poultry resulting in mortality, poor weight gains, poor feed conversion ratios (e.g. as measured by [total body weight gain]/[total feed consumed]), etc. The disease is addressed in commercial poultry with a variety of treatments including antibiotics and vaccines. The use of antibiotics in animal agriculture, in particular poultry production, is under increasing pressure from both consumers and government regulatory agencies. Thus, vaccines are becoming a common method of addressing coccidiosis in commercial poultry operations.
Vaccines are given to poultry to generate an appropriate immune response against Eimeria species. However, the use of vaccines in a semi-controlled dose of one or more fully virulent or attenuated Eimeria species as typically given to young poultry may result in a mild case of coccidiosis. Although mild, this still presents negative side effects in the poultry, which is displayed by a reduction in various production parameters in the poultry while they overcome the infection and create natural immunities to Eimeria species. Animal welfare and economically important disruptions result. For example, this decrease in production parameters translates into lost incomes when the birds are sent to market, especially in broiler birds where life cycle is short. In severe cases, adverse effects following coccidiosis vaccination requires treatment with anti-coccidial therapeutics. In other cases, an antibiotic is needed to control the secondary bacterial infection that often occurs post vaccination. A recovery from losses in these birds is generally believed to be impractical. While the use of vaccines may be an environmentally sound solution and alleviate some consumer concerns, it has substantial economic shortcomings.